Tires typically include a tread with a tread pattern that, when the tire is loaded, defines a footprint providing a frictional engagement with the road. Various tire constructions have been used to provide sufficient contact pressure at the shoulder during tire life while combating irregular wear and limiting heat generation in early life. However, these constructions have proven to be deficient in one regard or another.
One approach is to provide the shoulder rib with a step-off in which the whole shoulder rib is lowered relative to central tread regions. This construction, however, initiates irregular wear at an early mileage. Another approach is to use different types of decoupling grooves. Vertical decoupling grooves, which define a sacrificial shoulder rib, are prone to tearing that can propagate and result in shoulder rib tear. Side decoupling grooves are unproven and remain intact for most of the tire life, risking problems of fatigue at the deepest, rounded part. Dense shoulder blading is expensive, more so than molded grooves. Because shoulder blading is generally deep, it also increases the likelihood of crack formation.
For these and other reasons, it would be desirable to provide a pneumatic tire that addresses these and other deficiencies of typical pneumatic tires.